This application is related to commonly-assigned U.S. patent application Ser. No. 12/403,444, filed Mar. 13, 2009; and a concurrently filed GE application having Ser No. 13/291,208, filed herewith on Nov. 8, 2011.
The present invention relates to a combustion turbine engine and, more particularly, to an inlet heating system for a combustion turbine engine.
During some turbine operations, the turbine pressure ratio may reach an operating pressure ratio limit of the compressor. This may cause a compressor surge. The compressor pressure ratio may be larger than the turbine pressure ratio due to pressure losses across the combustor. Compressor pressure ratio protection typically involves bleeding and re-circulating discharge air to the compressor inlet. This operation, known as inlet bleed heat (IBH) control, also raises the temperature of the compressor inlet by mixing cooler ambient air with the bleed portion of the hot compressor discharge air.
Conventionally, to maintain compressor inlet temperatures within a small range, a large number of vertical manifolds are arranged between the bleed air and the compressor inlet. While the vertical manifolds provide mixing in the horizontal plane, temperature gradients can remain within the bleed air. This may make it difficult to maintain the compressor inlet temperature within the small range. Furthermore, a large number of vertical manifolds lead to a costly installation and maintenance processes.
For the foregoing reasons, there is a need for a simpler IBH system that reduces the temperature gradients. The system should use require fewer components and reduce the overall pressure drop across the inlet system.